you would just submit a new post and say what your MTF would be. I made one before, I've only made the symbol though. But my friend has also created one, but he doesn't have an account, anyway, do you this is a good idea?

I'm still not sure what the purpose of the exercise is, though. As I mention below, the way to make a new MTF is to write an article that sticks that involves the MTF. For example, I introduce MTF Rho-7 ("Doctors Without Mortars") in SCP-3966 and MTF Phi-12 ("Green Light") in SCP-2459. Do I expect them to be used again? No. However, because they're in successful articles, they are more "canon" (Caveat: There Is No Canon, etc.) than any amount of brainstorming we could do about who a group are, their backstories, their standard equipment, their names and families, how many reality benders they've killed, and so on.

Certainly starting out with a seed of "some random backstory" is pretty useless, though, because there's no story kernel to build on.

My advice is to work on an article that involves the MTF. Have any details you want to deliver regarding the MTF as part of the article, and make sure that every detail you do include is tied into the story and/or doesn't clutter up the article.

So basically it would be a forum game? Can't say I'm a fan. As for actually creating an MTF, you do that by using it in successful tales, SCP and GoI-Format articles. If you and several other authors incorporate the MTF into your work, it might be added to the MTF page if you put in a request.

Indeed, creating a new MTF occurs through writing it into stories and SCPs that survive. Otherwise, it's trivially easy to come up with one: pick out a letter and number, give it a title, and bam, instant MTF, fully formed (if still skeletal in character).

Well the most important part of any MTF is, of course, a clever nickname that relates to their operational focus. (Haha, just kidding! Kind of…)

There are a couple articles that use an MTF Application document as their format. But those are, like, supplementary parts to larger narratives.. The Mu-3 one, for example, serves as a primer to the larger tale they feature in; explaining how the MTF is structured and operates.

For something like that to interest readers as a stand-alone, would probably require an interesting and unique Stated Objective (or requirements to meet that objective) and to focus on that aspect.